Apparatus for transferring liquefied gases



Oct. 8, 1940.

H. BONNAUD APPARATUS FOR TRANSFERRING LIQUEFIED GASES Filed March 23, 1939 INVENTOR 3 00x100 ATTORNEY5 Patented Oct. 8, 1940 UNITED STATES PATENT I oF FIcE- APPARATUS roa TRANSFERRING LIQUEFIED GASES l Henri 'Bonnaud, Virofiay, France, assignor to LAir Liquide,Soci't Anonyme pour lEtude et IExploitation des Paris, France Procds Georges Claude,

ApplicationMarch 2a, 1939, Serial No. 263,656

, .v In France April 1, 1938 4 Claims. (01. 62-122) This invention relates to the 'handlingoi liquefied gases and particularly to an apparatus adapted to facilitate the withdrawal of liquid from an apparatus in which such liquid isproduced by 5 liquefaction and rectification of gaseous mixtures and the transference of the liquid to vessels for,

storage and transportation.

In the method of producing liquefied gases by liquefaction and rectification of gaseous mixtures, a liquid consisting of one of the constituents of the gaseous mixture may be accumulated in the rectificationcolumn. It is frequentlydesirable to withdraw such a liquid product and todeliver it i to vessels for transportation. In commercial operations, large volumes of such liquids are accumulated and transported in suitably insulated containers on trucks,railway cars, etc.

In the production of liquefied gases it is desirable that the liquefied gas in the liquefying ap-- 2o paratus be kept therein under as low a pressure as possible so that as the liquid in the apparatus is withdrawn the resultant pressure-drop will be reduced to a minimum and less vaporization of the liquid remaining-in theapparatus will take place. I

Liquefied gas withdrawn from the liquefying apparatus commonly is collected in heat-insulatedstorage vessels from which it is transferred to smaller vessels mounted on railway cars,- trucks or the like, for transportation to the place of use. Such transfer may be obtained by; gravity, by maintaining the liquefying apparatus: and storage vessel at an elevation higher than the transportable vessels to be, filled-from the storagevessel, but such-an installation is impractioaldue to-the height which it would be-necessary to maintain the liquefying apparatus and storage vessel. A special pump for liquefied gases may be used.

for transferring the liquefied gas from one vessel vantageousto obtain automaticallysuch atransfer of the liquefied gases by means of gaseous pressure exerted above the liquefied gas in the storage or other vessel to be emptied. However, a such transference ofthe liquefied gas seldom .can

be carried out when the storagev vessel is con-v nected to the rectifying apparatus as'the pressure created above the liquid in the storage vessel practically prevents the liquefied gas from fiow- 60 ing from the liquefying apparatus to the storage vesseL'and such stopping of the flow of the lique fied gas from the liquefying apparatus entails'an undesirable disturbance of the liquefying operation.

55 The patent to I-agardetNo. 1,998,629 discloses an apparatus which overcomes the above disadvantages in that the liquefied gas is conducted from the liquefying apparatus to a first vessel the apparatus disclosed in the aforesaid Lagarde patent, and which has further advantages resulting from the simplification of the procedure and -15 apparatus.

Inaccordance with the present invention a receptacle generally corresponding to one of the receptacles utilized 'inthe aforesaid patent is embodied in the liquefaction column, and preferably locatedabout'the heat exchange tubes in the vaporizingsection thereof. Thus the present invention results not only in Simplifying the structure, but also in havingthe further advantagethat it provides for maintaining a reserve :5 a, supply of liquefied" gas within the vaporizing;

section of the liquefaction column which will facilitate the starting of a column after it "has temporarily been shut down.-

Other objects and advantages of the invention 30 will'be apparent as it is better understood by reference to the following specification and the accompanying drawing, which illustrates diagrammatically a portion of a liquefaction column embodying my improvements, together with the 35 auxiliary equipment which is utilized therewith to facilitate the transfer of the liquefied gas from. the column without disturbing the operation thereof." 40 to another, but in many instances it. is more. ad-

In describing the invention, I shall refer to the 40 production of liquefied oxygen as an example, al-

though the invention may be utilized in a similar manner to transfer other liquefied gases from the source thereof to containers for storage-or transportation. Thus, any liquefied gas which is 5 produced and accumulated in a manner similar to the operation" of a liquefaction column for the separation of the elements of atmospheric air may be treated similarly in the transfer of the liquid from the source. i v

Referring to the drawing, 5 indicates'th'e shell of a conventional liquefaction column of which I have illustrated only that portion ordinarily known as the vaporizer, in which liquid oxygen, for example, accumulates as the result of rectification of liquids and gases in the upper portion of the column (not shown). It will be understood that the shell 5 is insulated in the usual manner to avoid, as far as possible, heat losses which are incidental a column. The accumulated liquid oxygen is delivered from the upper part of the column through a pipe 6 and accumulates in the space surrounding a plurality of tubes 1, communicating with the lower section of the column 8. Through these tubes, vapors rising from the lower section of the column travel upwardly to a head 9 and the tubes. The vapors conliquid flowing backwardly'to be received by collectors ID or to pass again into the lower of the column. The liquid nitrogen may be withdrawn through a pipe I l and utilized in the usual manner as reflux liquid at the top of the column.

In accordance with the present invention, I provide a cylindrical wall surrounding the space in which the liquid oxygen is accumulated,

affording a dam over which a quantity of liquid the output of the air separation apparatusuninterruptedly flows into oxygen corresponding to the annular space between the wall 12 and-the shell 5. This liquidoxygen is transferred from this space as will be explained hereinafter, while a sufficient body of liquid oxygen is maintained about the tubes 1 to perform its function of condensing nitrogen in the tubes.

To effect the transfer of theliquid oxygen, I provide a receptacle it which may-be of any suitable form, though preferably spherical, enclosed within a suitable sulating material between in quantity sufllcient to minimize heat losses. annular space into which the liquid oxygen overflows to the top of the receptacle l3, said pipe being provided with a valve i6.

A pipe i1 is connected to the receptacle l3 and is provided with a valve l8. Vapors which are formed incidentally by evaporation of liquid in the receptacle l3 escape through the pipe 11 while the valve i8 is open. A pipe I9 is similarly connected to the receptacle l3 and is provided with branches 20 and 2!, respectively having valves 22 and 23. The pipe 2i is connected to a source of gas under pressure which may be introduced through the pipe l9 to the interior of the receptacle lit. .The pipe 20 permits the withdrawal of gases and vapors from the receptacle i3, after the liquid has been expelled therefrom in tile manner hereinafter described. A pipe 24 is connected to the bottom of the receptacle l3, and is provided with a valve 25. The pipe 24 may be provided with a suitable connection (not shown), permitting the delivery of liquid to any suitable transportation or storage vessel. Both the pipes l5 and 25 are surrounded by casings 26 and 21, enclosing insulating material to avoid heat losses.

In the operation of the device as described, assuming that the receptacle I3 is empty and is to be filled with liquid oxygen, the valve 16 is opened. At the outset the annular space between the shell 5 and the wall i2 contains liquid oxygen, which flows into the r.-ceptacle l3. When all the liquid oxygen contained in this annular space above the level of the pipe l5 has been discharged, there only flows into the receptacle a quantity of liquid oxygen corresponding to the output of the liquefaction column. The valve i8 is opened atthe, same time as the valve IE to permit the discharg" to the operation of such surroundi are condensed by heat exchange with the liquid oxygen surrounding sist principally of nitrogen and are liquefied, the

section housing I with heat in- A A pipe i5 connects the of incidental vapors from the receptacle. When suflicient liquid has accumulated in the receptacle IS, the valves l6 and i8 are closed, the valve 25 is opened, the pipe 24 being then connected to a receiving vessel, and the valve 23 is opened to permit theintroduction of a suitable gas under pressure which forces the liquid from the receptacle I! through the pipe 24 into the receiving vessel. The annular space between the shell5 and the wall I2 is filling meanwhile; without any change occurring in the level of the liquid bath the tubes 1. When the receptacle i3 is empty, he valves 23 and 25 are closed, the

valves [5 and I! are, reopened and the cycle is repeated.

From the aforegoin it will be apparent that the present invention not only provides a simpler apparatus for obtaining the advantages of the apparatus of the aforesaid Lagarde patent, but

that it also provides for the maintaining of a reserve supply of liquid about the tubes 1 before stopping the operation of the liquefaction column,

thus facilitating the starting of the column after it has been temporarily shut down. Without this provision, the column would be drained of its reserve liquid and it would be necessary to accumulate liquid in the column to condense the nitrogen therein before the proper functioning of the. rectification apparatus could be established. This and other advantages facilitate the commercial application of the method and apparatus and ensure a more economical operation in respect to the transfer of liquid from the column.

to vessels for transportation and storage.

Various changes may be made in the form and arrangement of the structure and in the details of operation, without departing from the invention or sacrificing the advantages thereof.

I claim:

1. In a plant for recovering in the liquid state a constituent. of a low-boiling gaseous mixture, a separation section in which the liquid constituentis formed, a vaporising sectionwhich receives the liquid constituent from the separation section and in which a portion of said constituent is revaporised and from which the remaining liquid constituent may stream by overflow, a storage section for receiving such overflowing liquid constituent, a receptacle adapted to receive the liquid constituent; means for connecting said storage section with said receptacle, means for is adapted to pass, a liquefied-gas storage receptacle surrounding at least a portion of said tubes and adapted to maintain a predetermined level of liquid about said tubes, a compartment in said vaporizing section of the column adapted to receive liquefied gas from saidstorage receptacle, a storage vessel exterior of said column, a passage connecting said exterior storage vessel with said compartment, and means for discharging liquefied gas from said exterior storage vessel.

3. In a plant for recovering in a liquid state a constituent of a gaseous mixture, a liquefaction column having a vaporizing section positioned to receive liquefied gas from a rectification section, tubes in said vaporizing section through which gas to be cooled is adapted to pass, a wall spaced from the inside of the liquefaction column 'cool gases passing through'said tubes, said wall also cooperating with the surrounding wall of the liquefaction column to define a space for receiv- 0 ing liquefied gas from the receptacle about said tubes, a' storage vessel exterior of said column, a passage connecting said storage vessel with the space between the wall of the liquefaction column and the wall surrounding said tubes in the vaporizing section thereof, and means for discharging liquid from said storage vessel.

a constituent of a gaseous mixture, a liquefaction column having a vaporizing section positioned to receive liquefied gas from a rectification section,

tubes in said vaporizing section through which J gas to be cooled is adapted to pass, a wall spaced from theinside of the liquefaction column and surrounding said tubes, said wall forming a receptacle about said tubes forI receiving the liquid constituent from the rectification section of said column to act as a heat exchange mediumto cool Y gases passing through said tubes, said wall also cooperating with the surrounding wall of the liquefaction column to define a space for receiving liquefied gas from the receptacle about said tubes, a storage vessel exterior of said column, a passage connecting saidstorage vessel with the space between the wall of the liquefaction column and the wall surrounding said tubes in the vapor-' izing section thereof, a valve for interrupting the flow of liquidthrough said passage, means'for introducing a gas under pressure above the level of 4. In a plant for recovering in a liquid state the liquid in said exterior storage vessel, and means for withdrawing a liquidfrom said-exterior receptacle simultaneously with the introduction of a gas under pressure above the level thereof. J a

HENRI BONNIiUD. 

